盐胁迫下大豆转录因子GmTFIIIC功能研究

Functional Characterization of GmTFIIIC in Response to Salt Stress

大豆是中度耐盐植物,土壤盐碱化会对大豆产量及品质造成严重影响。因此挖掘耐盐基因,提高大豆耐盐能力十分必要。真核生物中,转录因子TFIIIC作为RNA聚合酶III转录机制的辅助因子,其转录活性易受到外部因素的影响,进而影响tRNA基因转录效率和蛋白质的合成。本课题组前期研究发现大豆GmTFIIIC在盐胁迫下上调表达,但目前大豆GmTFIIIC的抗逆功能还不清楚。本研究通过大豆发状根体系,将GmTFIIIC基因过表达,进行盐胁迫下转基因复合体植株表型及生理指标分析,研究大豆GmTFIIIC基因在盐胁迫下的功能。结果表明:GmTFIIIC基因过表达,盐胁迫条件下,大豆转基因复合体根、茎的Na^+/K^+要低于野生型空载对照;叶片叶绿素相对含量高于野生型空载对照;叶片H2O2和O2^-含量低于野生型空载对照;叶片含水率高于空载对照,表明大豆发状根中过表达GmTFIIIC基因提高了大豆转基因复合体的耐盐能力。研究结果为大豆GmTFIIIC基因耐盐功能研究提供理论基础。

The cultivated soybean varieties are moderate tolerant under salt stress,but soil salinization seriously threats the soybean yield and quality.Characterization of the salt-tolerant genes might be suitable for the genetic improvement of salt tolerance.In eukaryotes,transcription factor IIIC(TFIIIC)generally interacts with transcription factor IIIB(TFIIIB)on RNA polymerase III to regulate tRNA gene transcription,which in turn affects protein synthesis.In our previous study,we found that TFIIIC was up-regulated in soybean root under salt stress.However,the gene function of GmTFIIIC remains unknown under high salinity stress.In this study,we characterized the GmTFIIIC function in transgenic complex,in which the GmTFIIIC over-expression was conducted by transforming the soybean hairy roots.The results showed that the Na^+/K^+ of roots and shoots in the GmTFIIIC overexpression complex were lower than that in the vacant control complex.While the relative content of chlorophyll and water in leaves was higher,and the content of H2O2 and O2^- was lower than that of the vacant control complex,which indicates that the salt tolerance in transgenic complex is enhanced by GmTFIIIC overexpression.Thus,the results might contribute to a better understanding of the molecular mechanism of GmTFIIIC in responding to salt stress.